Information Technology Reference
In-Depth Information
Now, to see the inbound matching process in its entirety, imagine that there is no VoIP
dial peer 1101 on ROUTER_B, as shown in Figure 6-11.
dial-peer voice 2510 voip
destination-pattern 2510
session target ipv4:10.1.1.2
dial-peer voice 2510 pots
destination-pattern 2510
no digit-strip
port 1/0:1
Call Leg 1
Call Leg 2
Call Leg 3
Call Leg 4
10.1.1.2/24
FXS 1/0/0
T1 1/0
10.1.1.1/24
V
IP WAN
x1101
x2510
ROUTER_B
CME_A
dial-peer voice 1101 pots
destination-pattern 1101
port 1/0/0
Figure 6-11
Matching Inbound Dial Peers Using Dial Peer 0
The first result is that you could not place calls to x1101 from ROUTER_B (or the PBX
system attached to ROUTER_B). However, what if x1101 called x2510? The CME_A and
ROUTER_B routers have enough information to match the outbound call legs.
ROUTER_B is just missing the information for the inbound dial peer (call leg 3). Here's
how the decision process would flow:
1.
(NO MATCH) 2510 (the dialed number) does not match an
incoming called-number
dial peer configuration command on ROUTER_B, because this command does not
exist in the configuration.
2.
(NO MATCH) x1101 caller ID information (ANI) does not match an
answer-address
dial peer configuration command on ROUTER_B, because this command does not
exist in the configuration.
3.
(NO MATCH) x1101 caller ID information (ANI) does not match the
destination-
pattern
dial peer configuration command, because the VoIP dial peer 1101 was re-
moved on ROUTER_B.
4.
(NO MATCH) x1101 did not come in a POTS interface (FXS, FXO, E&M, Voice
BRI/T1/E1 digital interface) that could be matched using the
port
command; rather,
x1101 came across a VoIP connection.
5.
(MATCH) Because ROUTER_B could not find a match using the previous four meth-
ods, it uses dial peer 0.
So, this now begs the question, “What is dial peer 0?” Dial peer 0 is like a default gateway
dial peer that appears when there is no dial peer match (this applies only for inbound dial
peers, not for outbound dial peers). Although this allows the call to complete, you have no
control over dial peer 0. You cannot configure it nor change any of its default settings.
Dial peer 0 uses the following, unchangeable settings:
